In this activity, students take the mass of a piece of sidewalk chalk and are guided to draw the structure of calcium carbonate (chalk) on the sidewalk with sidewalk chalk. At the end, the students take the mass of the remaining chalk, and then calculate how many formula units of Calcium Carbonate were used in their drawing.
This activity is a good review for the following concepts:
atomic structure, ions, covalent vs. ionic bonding, mass, polyatomic ions.
This activity should be used after the mole and basic stoichiometry is introduced.
*Note: Some chalk is composed of Calcium Sulfate and not Calcium Carbonate. You can change the lab if you wish to whatever you want.